<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title>Vue 条件</title>
    <script src="https://unpkg.com/vue"></script>
</head>
<body>
<div id="app-3">
    <p v-if="seen">你现在看见我了</p>
</div>
<script>
    var app3=new  Vue({
        el:'#app-3',
        data:{
            seen:true
        }

    })

</script>

</body>

</html>